ISO/IEC DIS 21838-4 Information technology - Top-level ontologies (TLO) - Part 4: TUpper

PSL is being incorporated into the TUpper ontology as Part 4 of ISO 21838 (Top Level Ontologies). In particular, TUpper extends PSL with modules for physical objects, location, and units of measure, thus addressing the shortcomings of using PSL alone. In these notes, we summarize various aspects of PSL and TUpper with respect to the IOF selection criteria for a foundational ontology.